. >>> a study published in britain find women sitting for long periods of time could develop deadly blood clots in their lungs. those who spent 41 hours or more a week sitting when they weren't at work were twice as likely to develop a potentially life threaten pulmonary embolism. >> >>> new research found chantix may increase your risk of heart disease. >> joining us is senior medical correspondent elizabeth cohen. if it worked to stop you smoking, is the risk worth it and then you don't take it once you you've stopped smoking? tell us how this is working out. >> each person is different. it really depends. some people take this drug and it helps them quit smoking and they are able to continue taking it. other people take this drug and maybe it helps them quit smoking but maybe it also makes them more likely to have a heart attack, and so you have to talk to your doctor and figure out sort of, you know, help think about which camp you might fall into, how long do you want to take the drug for. there's so many different things in play. ali, i want to tell you about another issue with this